Light-emitting device

Abstract

A light-emitting device includes a broadband chip and an encapsulant. A full width at half maximum (FWHM) of the broadband chip is greater than or equal to 20 nanometers. The encapsulant is coated on the broadband chip. The encapsulant includes red fluoride phosphor. According to the light-emitting device, the encapsulant layer with red fluoride phosphor is excited by using the broadband chip with the FWHM greater than or equal to 20 nanometers, so that the light-emitting device can emit white light with high light efficiency and low color shift value, thereby solving the problem of serious color shift caused by red fluoride phosphor.

What is claimed is: 
     
         1 . A light-emitting device, comprising:
 a broadband chip, wherein a full width at half maximum (FWHM) of the broadband chip is greater than or equal to 20 nanometers; and   an encapsulant, coated on the broadband chip, wherein the encapsulant comprises red fluoride phosphor.   
     
     
         2 . The light-emitting device as claimed in  claim 1 , wherein a luminescence spectrum of the broadband chip has a plurality of peaks, the luminescence spectrum of the broadband chip has at least one peak in a range of 432.5 to 450 nanometers; a first peak from 432.5 to 450 nanometers is defined as a first peak turning point, and a peak adjacent to the first peak turning point on a long wavelength side is defined as a second peak turning point. 
     
     
         3 . The light-emitting device as claimed in  claim 2 , wherein a wavelength value of the second peak turning point differs from that of the first peak turning point by 8 to 20 nanometers. 
     
     
         4 . The light-emitting device as claimed in  claim 2 , wherein an intensity ratio of the second peak turning point to the first peak turning point at an operating temperature of 85° C. is greater than that at an operating temperature of 25° C. 
     
     
         5 . The light-emitting device as claimed in  claim 4 , wherein the intensity ratio of the second peak turning point to the first peak turning point is in a range of 50%-100% at the operating temperature of 25° C.; and the intensity ratio of the second peak turning point to the first peak turning point is in a range of 60%-150% at the operating temperature of 85° C. 
     
     
         6 . The light-emitting device as claimed in  claim 1 , wherein a color coordinate shift distance of light emitted by the light-emitting device at an operating temperature of 85° C. and light emitted by the light-emitting device at an operating temperature of 25° C. is not more than 0.006. 
     
     
         7 . The light-emitting device as claimed in  claim 1 , wherein a ratio of a spectral intensity of the broadband chip at a wavelength of 460 nanometers to a spectral intensity at a wavelength of 440 nanometers at an operating temperature of 85° C. is a first ratio; and a ratio of the spectral intensity of the broadband chip at the wavelength of 460 nanometers to the spectral intensity at the wavelength of 440 nanometers at an operating temperature of 25° C. is a second ratio; and
 wherein the first ratio is greater than the second ratio. 
 
     
     
         8 . The light-emitting device as claimed in  claim 1 , wherein the broadband chip is multiple in number, and a distance between a color coordinate center of light emitted by the light-emitting device at an operating temperature of 85° C. and a color coordinate center of light emitted by the light-emitting device at an operating temperature of 25° C. does not exceed three standard deviation of color matching (SDCM). 
     
     
         9 . The light-emitting device as claimed in  claim 1 , wherein the encapsulant further comprises at least one of yellow-green phosphor and red nitride phosphor, and the encapsulant is coated on the broadband chip to form a single encapsulant layer. 
     
     
         10 . The light-emitting device as claimed in  claim 1 , wherein the encapsulant comprises a first encapsulant layer and a second encapsulant layer; the first encapsulant layer is arranged on the broadband chip, and the second encapsulant layer is arranged on a side of the first encapsulant layer facing away from the broadband chip; the first encapsulant layer comprises the red fluoride phosphor, and the second encapsulant layer comprises at least one of yellow-green phosphor and red nitride phosphor. 
     
     
         11 . The light-emitting device as claimed in  claim 1 , wherein the FWHM of the broadband chip is greater than 25 nanometers. 
     
     
         12 . A light-emitting device, comprising:
 a broadband chip, wherein an FWHM of the broadband chip is greater than or equal to 20 nanometers; and   an encapsulant, coated on the broadband chip, wherein the encapsulant comprises red fluoride phosphor;   wherein a color rendering index (CRI) of the light-emitting device is greater than 90.   
     
     
         13 . The light-emitting device as claimed in  claim 12 , wherein a color coordinate shift distance of light emitted by the light-emitting device at an operating temperature of 85° C. and light emitted by the light-emitting device at an operating temperature of 25° C. is not more than 0.006. 
     
     
         14 . The light-emitting device as claimed in  claim 12 , wherein a ratio of a spectral intensity of the broadband chip at a wavelength of 460 nanometers to a spectral intensity at a wavelength of 440 nanometers at an operating temperature of 85° C. is a first ratio; and a ratio of the spectral intensity of the broadband chip at the wavelength of 460 nanometers to the spectral intensity at the wavelength of 440 nanometers at an operating temperature of 25° C. is a second ratio; and
 wherein the first ratio is greater than the second ratio. 
 
     
     
         15 . The light-emitting device as claimed in  claim 12 , wherein the encapsulant further comprises at least one of yellow-green phosphor and red nitride phosphor, and the encapsulant is coated on the broadband chip to form a single encapsulant layer. 
     
     
         16 . A light-emitting device, comprising:
 a broadband chip, wherein a luminescence spectrum of the broadband chip has a plurality of peaks; and   an encapsulant, coated on the broadband chip, wherein the encapsulant comprises red fluoride phosphor.   
     
     
         17 . The light-emitting device as claimed in  claim 16 , the luminescence spectrum of the broadband chip has at least one peak in a range of 432.5 to 450 nanometers; a first peak from 432.5 to 450 nanometers is defined as a first peak turning point, and a peak adjacent to the first peak turning point on a long wavelength side is defined as a second peak turning point. 
     
     
         18 . The light-emitting device as claimed in  claim 17 , wherein a wavelength value of the second peak turning point differs from that of the first peak turning point by 8 to 20 nanometers. 
     
     
         19 . The light-emitting device as claimed in  claim 16 , wherein a ratio of a spectral intensity of the broadband chip at a wavelength of 460 nanometers to a spectral intensity at a wavelength of 440 nanometers at an operating temperature of 85° C. is a first ratio; and a ratio of the spectral intensity of the broadband chip at the wavelength of 460 nanometers to the spectral intensity at the wavelength of 440 nanometers at an operating temperature of 25° C. is a second ratio; and
 wherein the first ratio is greater than the second ratio. 
 
     
     
         20 . The light-emitting device as claimed in  claim 16 , wherein the encapsulant further comprises at least one of yellow-green phosphor and red nitride phosphor, and the encapsulant is coated on the broadband chip to form a single encapsulant layer.